/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2010 Amaury Pouly
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include "crypto.h"

/* Table extracted from firmware, don't know if this is regular CRC32 */

static uint32_t crc_table[256] = {
    0x0, 0x4C11DB7, 0x9823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B, 0x1A864DB2,
    0x1E475005, 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6, 0x2B4BCB61, 0x350C9B64,
    0x31CD86D3, 0x3C8EA00A, 0x384FBDBD, 0x4C11DB70, 0x48D0C6C7, 0x4593E01E,
    0x4152FDA9, 0x5F15ADAC, 0x5BD4B01B, 0x569796C2, 0x52568B75, 0x6A1936C8,
    0x6ED82B7F, 0x639B0DA6, 0x675A1011, 0x791D4014, 0x7DDC5DA3, 0x709F7B7A,
    0x745E66CD, 0x9823B6E0, 0x9CE2AB57, 0x91A18D8E, 0x95609039, 0x8B27C03C,
    0x8FE6DD8B, 0x82A5FB52, 0x8664E6E5, 0x0BE2B5B58, 0x0BAEA46EF, 0x0B7A96036,
    0x0B3687D81, 0x0AD2F2D84, 0x0A9EE3033, 0x0A4AD16EA, 0x0A06C0B5D, 0x0D4326D90,
    0x0D0F37027, 0x0DDB056FE, 0x0D9714B49, 0x0C7361B4C, 0x0C3F706FB, 0x0CEB42022,
    0x0CA753D95, 0x0F23A8028, 0x0F6FB9D9F, 0x0FBB8BB46, 0x0FF79A6F1, 0x0E13EF6F4,
    0x0E5FFEB43, 0x0E8BCCD9A, 0x0EC7DD02D, 0x34867077, 0x30476DC0, 0x3D044B19,
    0x39C556AE, 0x278206AB, 0x23431B1C, 0x2E003DC5, 0x2AC12072, 0x128E9DCF,
    0x164F8078, 0x1B0CA6A1, 0x1FCDBB16, 0x18AEB13, 0x54BF6A4, 0x808D07D,
    0x0CC9CDCA, 0x7897AB07, 0x7C56B6B0, 0x71159069, 0x75D48DDE, 0x6B93DDDB,
    0x6F52C06C, 0x6211E6B5, 0x66D0FB02, 0x5E9F46BF, 0x5A5E5B08, 0x571D7DD1,
    0x53DC6066, 0x4D9B3063, 0x495A2DD4, 0x44190B0D, 0x40D816BA, 0x0ACA5C697,
    0x0A864DB20, 0x0A527FDF9, 0x0A1E6E04E, 0x0BFA1B04B, 0x0BB60ADFC, 0x0B6238B25,
    0x0B2E29692, 0x8AAD2B2F, 0x8E6C3698, 0x832F1041, 0x87EE0DF6, 0x99A95DF3,
    0x9D684044, 0x902B669D, 0x94EA7B2A, 0x0E0B41DE7, 0x0E4750050, 0x0E9362689,
    0x0EDF73B3E, 0x0F3B06B3B, 0x0F771768C, 0x0FA325055, 0x0FEF34DE2, 0x0C6BCF05F,
    0x0C27DEDE8, 0x0CF3ECB31, 0x0CBFFD686, 0x0D5B88683, 0x0D1799B34, 0x0DC3ABDED,
    0x0D8FBA05A, 0x690CE0EE, 0x6DCDFD59, 0x608EDB80, 0x644FC637, 0x7A089632,
    0x7EC98B85, 0x738AAD5C, 0x774BB0EB, 0x4F040D56, 0x4BC510E1, 0x46863638,
    0x42472B8F, 0x5C007B8A, 0x58C1663D, 0x558240E4, 0x51435D53, 0x251D3B9E,
    0x21DC2629, 0x2C9F00F0, 0x285E1D47, 0x36194D42, 0x32D850F5, 0x3F9B762C,
    0x3B5A6B9B, 0x315D626, 0x7D4CB91, 0x0A97ED48, 0x0E56F0FF, 0x1011A0FA,
    0x14D0BD4D, 0x19939B94, 0x1D528623, 0x0F12F560E, 0x0F5EE4BB9, 0x0F8AD6D60,
    0x0FC6C70D7, 0x0E22B20D2, 0x0E6EA3D65, 0x0EBA91BBC, 0x0EF68060B, 0x0D727BBB6,
    0x0D3E6A601, 0x0DEA580D8, 0x0DA649D6F, 0x0C423CD6A, 0x0C0E2D0DD, 0x0CDA1F604,
    0x0C960EBB3, 0x0BD3E8D7E, 0x0B9FF90C9, 0x0B4BCB610, 0x0B07DABA7, 0x0AE3AFBA2,
    0x0AAFBE615, 0x0A7B8C0CC, 0x0A379DD7B, 0x9B3660C6, 0x9FF77D71, 0x92B45BA8,
    0x9675461F, 0x8832161A, 0x8CF30BAD, 0x81B02D74, 0x857130C3, 0x5D8A9099,
    0x594B8D2E, 0x5408ABF7, 0x50C9B640, 0x4E8EE645, 0x4A4FFBF2, 0x470CDD2B,
    0x43CDC09C, 0x7B827D21, 0x7F436096, 0x7200464F, 0x76C15BF8, 0x68860BFD,
    0x6C47164A, 0x61043093, 0x65C52D24, 0x119B4BE9, 0x155A565E, 0x18197087,
    0x1CD86D30, 0x29F3D35, 0x65E2082, 0x0B1D065B, 0x0FDC1BEC, 0x3793A651,
    0x3352BBE6, 0x3E119D3F, 0x3AD08088, 0x2497D08D, 0x2056CD3A, 0x2D15EBE3,
    0x29D4F654, 0x0C5A92679, 0x0C1683BCE, 0x0CC2B1D17, 0x0C8EA00A0, 0x0D6AD50A5,
    0x0D26C4D12, 0x0DF2F6BCB, 0x0DBEE767C, 0x0E3A1CBC1, 0x0E760D676, 0x0EA23F0AF,
    0x0EEE2ED18, 0x0F0A5BD1D, 0x0F464A0AA, 0x0F9278673, 0x0FDE69BC4, 0x89B8FD09,
    0x8D79E0BE, 0x803AC667, 0x84FBDBD0, 0x9ABC8BD5, 0x9E7D9662, 0x933EB0BB,
    0x97FFAD0C, 0x0AFB010B1, 0x0AB710D06, 0x0A6322BDF, 0x0A2F33668, 0x0BCB4666D,
    0x0B8757BDA, 0x0B5365D03, 0x0B1F740B4
};

uint32_t crc(byte *data, int size)
{
    return crc_continue(0xffffffff, data, size);
}

uint32_t crc_continue(uint32_t previous_crc, byte *data, int size)
{
    uint32_t c = previous_crc;
    /* normal CRC */
    for(int i = 0; i < size; i++)
        c = crc_table[data[i] ^ (c >> 24)] ^ (c << 8);
    return c;
}
